Real-Time Physics Simulation Forum

Hello everyone, I'm trying to include slider constraints into my bullet project after having successfully included 6dof, ball socket and hinge. With sliders however, I have surprisingly bad results. Basically, each object only ever seems to travel along it's X Axis. I found an old thread in this for...

I'm not sure if I answer correctly but I answer nonetheless as I build on Windows successfully .-) About the errors concerning GLUT: Don't worry about them. Unless you actually have GLUT in your environment and plan to use it, e.g. for debug output. I get the same errors and just ignore them. Also, ...

A semi-solution here: It appears to be possible to emulate a ball socket constraint using a generic 6dof constraint. With this, you can activate the 3 angular motors and achieve the desired effect. The constraint is quite unstable though. Gravity lets the objects slowly fall. You have to crank up it...

Hello, On another occasion I have simulated rotation friction on a hinge constraint by using the angular motor with target speed 0. Which works OK. Now my question is, is there a similar trick to emulate friction on a cone twist constraint as well? I tried the motor but it requires a target rotation...

Thanks for the clarification. I understand this is all stuff that is supposed to be handled in the simulation substep handler. So far I only extract collision information in there. Looks like there's way more to be done. I'll look into it. BTW, maybe someone can point me to a good starting point? Li...

Most certainly sounds like you have too few iterations and too large a time step. Try something like 500 iterations at 1/500 maximum step size (don't forget to take into account the maxSubStep, should be high enough that frame-rate drops won't mess with physics, unless of course you want the door t...

Well, there's limits as to what I can do here because we actually expose many of these values to the user. The system we are building here is like a physical world building blocks like things. The user can import meshes into the system and then freely set the mass of each object. The local inertia v...

There's one more thing that puzzles me about that hinge. It allows for an amazing amount of movement of the hinge axis. Considering a door example, if I have a dynamic object push the door open it will do so, but the actual door will wobble in it's hinge quite a bit. From visual judgement I would sa...

Right, I couldn't find an answer to all the questions by myself but in case anyone is interested I have a few things. There seems to be no generic way to solve this. By taking the ConstraintDemo examples and applying that to my own use case I found a way to at least make the constraint "weaker&...

A little update here. I have tried all sorts of iteration limits for this now an I cannot see any effect at all. So I guess it's huge motor impulse for now.

Thanks,
Moose

Hello, I am in the final stages of a bullet based project about integrating bullet into a large commercial visualizations system. It has been challenging, interesting and also a lot of fun to see things moving in a natural like fashion. Much like the ConstraintDemo we are using 6dof generic constrai...

You are saying that my solution is not the preferred (as in right) way?
I have tried to set the iterations to 50 which had no effect. I'm gonna try 200 and see what it does.

About direct solvers, I don't know what that is. Would you care to elaborate please?

Thanks,

Moose

I just stumbled over the same issue, replacing 2.81 by 2.82 here.
You should use <bullet_project_name>_SOURCE_DIR rather than CMAKE_SOURCE_DIR, that's for sure.

Flix,

thanks for your response. As it so happens, you were right. I sort of figured that out trying wild combinations at the same time. If I set the max impulse very high, it has the desired effect. Like that:

hinge_constraint->enableAngularMotor(true, 0 , 100000.0);

Thanks for the help.

Moose

Hello, I need a hinge constraint with friction to simulate a certain resistance when a user interacts with an object. Now in this forum I read I can use an angular motor like this: hinge_constraint->enableAngularMotor(true, 0.0, 0.02); I understand this is to create a motor with a target velocity of...